Although the physical design of communications and electronics systems has in recent years seen extensive advances in terms of simplification, miniaturization, ciruit integration, and the like, the interconnection between system components and mounting frames still relies largely on individual conductors assembled in cables for power distribution and signal transmission. In most systems, terminations from the many circuit units are collected at common points where terminals are provided to which individual cable conductors are joined. Although the art has offered improvements in terminating arrangements for making the electrical connections between the terminals and individual conductors, the problems of facilitating and speeding the individual joining of conductors and terminals without adding complexity and cost remain.
One well-known solderless connection arrangement employs a terminal presenting a bifurcated blade which is adapted to slice through the conductor insulation, which blade at the same time seizes the bared conductor to make the electrical connection. This arrangement has the obvious advantages that, not only is the tedious and time-consuming previous soldering step eliminated, but the necessity for first stripping the conductor insulation is also avoided. Conventionally, the individual cable conductors are first sorted and arranged on a first insulative member mounting the conductors in a pattern corresponding to the spacings of terminal blades retained in a second insulative block member. The two members are adapted to be fitted one to the other during which the blades function as described to make the electrical connections. A unitary connector assembly is thus realized which may be readily separated to permit wiring changes and repair of the connections.
As mentioned, such insulation piercing connections have long been known in the art. One such connector arrangement is disclosed, for example, in the patent of B. C. Ellis, Jr., U.S. Pat. No. 3,611,264, issued Oct. 5, 1971, in which arrangement a plurality of bifurcated blade terminals make simultaneous electrical connections with corresponding conductors held in alignment between the teeth of an indexing strip. In this and other known arrangements, single conductors make contact with individual bladed terminals. It frequently becomes necessary, however, to terminate more than one conductor on a corresponding individual bladed terminal. A bladed terminal for making such two-conductor connections is disclosed, for example, in the patent of R. P. Reavis, Jr., U.S. Pat. No. 4,040,446, issued Sept. 6, 1977. A terminal is there described which incorporates two bifurcated blades in one terminal structure, the blades lying one above the other. The cutting portions of the blades, however, appear at opposite ends of the bifurcations, that is, the cutting portion of one blade is presented at the open end of the bifurcation while that portion of the other blade is presented at the base of the bifurcation. A first conductor, as it is manually forced between both blade bifurcations, is seated to the base of the latter blade where its insulation is pierced. A second conductor is then also forced between both blade bifurcations but only so far as the cutting edges of the other blade at its open end. Two conductors are thus sequentially connected to the two-bladed terminal. Although dual connections to a single terminal may in this manner be reliably achieved, the individual insertion of what, in many cases, may be large numbers of conductor pairs in their respective double-bladed terminals remains tedious and time-consuming and, therefore, costly.
Typically, electrical connector arrangements of the character described in the foregoing also provide some form of strain relief for the cable conductors. This is frequently necessary to prevent inadvertent interruption of the electrical connections by sudden stresses applied to the conductors. This conductor strain relief has in the past been provided by adding structure integral with the connector assembly or by such structure comprising an adjunct to the assembly. In either case, the strain relief means has added to complexity and, therefore, cost to the connector assembly. It is to the problems of simplifying and facilitating the connection of large numbers of conductor pairs to their respective individual terminals to which the connector arrangement of this invention is chiefly directed. The connector arrangement of the invention is also directed to the associated problem of simplifying the means for achieving conductor strain relief.